d and f BLOCK ELEMENTS

Which property of transition metals is most directly linked to their ability to act as catalysts in hydrogenation reactions?

• High melting point
• High density
• Variable oxidation states and availability of d orbitals
• Large atomic radius

What is the main reason why copper is considered 'noble' compared to other first series transition metals?

• It is the most abundant
• It has the highest melting point
• It has a higher reduction potential and is less reactive towards acids
• It forms only +1 oxidation state

In the Contact Process for sulfuric acid production, what is the primary role of the vanadium pentoxide catalyst?

• To increase the equilibrium yield
• To change the reaction stoichiometry
• To lower the activation energy for SO2 oxidation
• To act as a reactant

What property of transition metal complexes is primarily responsible for the coloration of many paints and pigments?

• Ionic bonding
• Metallic bonding
• d-d electronic transitions
• Covalent network structure

Which transition metal's compounds are primarily responsible for the red color in ruby gemstones?

• Iron
• Cobalt
• Chromium
• Manganese